The skin may be considered to be the largest and most visible kind of biological tissue of the human body. It reflects the health of the body and acts as a barrier against injury and bacteria. Numerous invasive and non-invasive techniques are used for treating or diagnosing a condition of a skin. The invasive techniques require incisions and suturing of the skin. The non-invasive techniques treat the skin therapeutically that preserves the tissue from incisions and suturing. The non-invasive techniques may use various substances or energy from various regions of the electromagnetic spectrum, such as light, ultrasound, radio frequency, to treat the skin.
In recent years, the technologies, which use various light sources, to treat skin conditions, have been commercialized into numerous devices that remove unwanted hair, wrinkles, fine lines and various facial blemishes, tattoos, and vascular and pigmented lesions. The light, when applied directly to the human body, is absorbed by the various targets, for example, hemoglobin in the blood; the water in the skin; the melanin in the skin; or by the melanin in the hair follicles, depending on the wavelength of the light used and properties of the targets. Therefore, lasers generating coherent, monochromatic light were found early on to have different properties, each being preferable for specific procedures. In addition to lasers, several manufacturers have also introduced devices using broadband sources, which emit light of a range of wavelengths that practitioners then filter to select the appropriate wavelength for a specific treatment. Typically, with conventional skin treatment technologies there is a very fine line between effectiveness and collateral damage of the skin. Generally, light of shorter wavelengths has higher absorption efficiency. For example, blue and green light is highly absorbed not only by a target, but also by the tissue surrounding a target, which impacts the effectiveness of the treatment. Traditional lasers and light based systems require more power to compensate for the loss of the light due to reflection, scattering and absorption by the surrounding tissue that rises a risk of collateral damage of the surrounding tissue.
FIG. 1 is a diagram 100 illustrating the skin. As shown in FIG. 1, the outer most layer of the skin is epidermis 101, which covers dermis 102. The thickness of epidermis 101 is typically between 50 to 100 microns. As shown in FIG. 1, epidermis 101, dermis 102 and subcutaneous tissue 103 contain potential targets, e.g., hair follicles, dermal vessels, and pigmentary lesions, for therapy. As shown in FIG. 1, dermis 102 contains sebaceous gland 104, hair bulbs 105, and nerve endings 106. Sebaceous glands 104 secrete an oily substance called sebum. In humans, sebaceous glands 104 are primarily found in association with hair follicles but also occur in hairless areas of the skin. Sebum is a mixture of fat and the debris of dead fat-producing cells. These cells are constantly replaced by new growth at the base of the glands. Generally the sebum is deposited on the hair inside the follicles and is brought up to the surface of the skin along the hair shaft 110. In hairless areas, the sebum may surface through ducts. Sebum lubricates and protects the hair and skin and prevents drying and irritation of membranes. Excessive secretions of sebum may be related to acne, certain forms of baldness, and other skin disorders. As shown in FIG. 1, sebaseous glands 104 is covered by the epidermis 101 that complicates an access to the sebaseous glands 104. For example, one of the problems with current methods of applying medicines to treat acne is the difficulty of getting the medicine into the sebaceous gland. In addition, extraction of sebum directly from the sebaseous glands 104 is complicated.
As shown in FIG. 1, subcutaneous tissue 103 contains blood vessels 107, sweat glands 108, and cutaneous nerves 109. Blood vessels 107 provide nourishment to the overlying epidermis 101. The layers of the epidermis 101 may be peeled off using chemical or mechanical means to treat scarring, lines, wrinkles, sun damage, pigmentation disorders and certain types of skin lesions. The peeling off the layers of epidermis 101 refers to a skin resurfacing technique, e.g., a microdermabrasion technique, which uses tiny crystals of an abrasive material to peel off the layers of epidermis 101.
Conventional therapeutic technologies, however, may be inefficient in delivering energy or substance to a target due to the substantial loss of the energy or substance in the surrounding tissue and competing dermal and epidermal elements. In addition, conventional therapeutic technologies may require large amounts of energy or substance to treat the skin that compromises epidermal safety and the patient's comfort.